diff options
| author | Will Deacon <will@kernel.org> | 2020-05-28 18:00:51 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-28 18:00:51 +0100 |
| commit | d27865279f12035c730818aa1a0280fada866a37 (patch) | |
| tree | 5c4462885c2a6d7453b34ceb51d39b390030a2a6 | |
| parent | 342403bcb4dfe41324a0f6f4cb5a8d324f31c725 (diff) | |
| parent | a4eb355a3fdad85d16e4b098e8d56bb28b812ce0 (diff) | |
Merge branch 'for-next/bti' into for-next/core
Support for Branch Target Identification (BTI) in user and kernel
(Mark Brown and others)
* for-next/bti: (39 commits)
arm64: vdso: Fix CFI directives in sigreturn trampoline
arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
arm64: bti: Fix support for userspace only BTI
arm64: kconfig: Update and comment GCC version check for kernel BTI
arm64: vdso: Map the vDSO text with guarded pages when built for BTI
arm64: vdso: Force the vDSO to be linked as BTI when built for BTI
arm64: vdso: Annotate for BTI
arm64: asm: Provide a mechanism for generating ELF note for BTI
arm64: bti: Provide Kconfig for kernel mode BTI
arm64: mm: Mark executable text as guarded pages
arm64: bpf: Annotate JITed code for BTI
arm64: Set GP bit in kernel page tables to enable BTI for the kernel
arm64: asm: Override SYM_FUNC_START when building the kernel with BTI
arm64: bti: Support building kernel C code using BTI
arm64: Document why we enable PAC support for leaf functions
arm64: insn: Report PAC and BTI instructions as skippable
arm64: insn: Don't assume unrecognized HINTs are skippable
arm64: insn: Provide a better name for aarch64_insn_is_nop()
arm64: insn: Add constants for new HINT instruction decode
arm64: Disable old style assembly annotations
...
75 files changed, 963 insertions, 219 deletions
diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst index 41937a8091aa..314fa5bc2655 100644 --- a/Documentation/arm64/cpu-feature-registers.rst +++ b/Documentation/arm64/cpu-feature-registers.rst @@ -176,6 +176,8 @@ infrastructure: +------------------------------+---------+---------+ | SSBS | [7-4] | y | +------------------------------+---------+---------+ + | BT | [3-0] | y | + +------------------------------+---------+---------+ 4) MIDR_EL1 - Main ID Register diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst index 7dfb97dfe416..84a9fd2d41b4 100644 --- a/Documentation/arm64/elf_hwcaps.rst +++ b/Documentation/arm64/elf_hwcaps.rst @@ -236,6 +236,11 @@ HWCAP2_RNG Functionality implied by ID_AA64ISAR0_EL1.RNDR == 0b0001. +HWCAP2_BTI + + Functionality implied by ID_AA64PFR0_EL1.BT == 0b0001. + + 4. Unused AT_HWCAP bits ----------------------- diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 38b606991065..9969bf4c0c44 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -543,6 +543,7 @@ encoded manner. The codes are the following: hg huge page advise flag nh no huge page advise flag mg mergable advise flag + bt - arm64 BTI guarded page == ======================================= Note that there is no guarantee that every flag and associated mnemonic will diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 8d33d7fed6d8..697e6d80963b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -9,6 +9,7 @@ config ARM64 select ACPI_MCFG if (ACPI && PCI) select ACPI_SPCR_TABLE if ACPI select ACPI_PPTT if ACPI + select ARCH_BINFMT_ELF_STATE select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DMA_PREP_COHERENT @@ -32,6 +33,7 @@ config ARM64 select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST + select ARCH_HAVE_ELF_PROT select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_INLINE_READ_LOCK if !PREEMPTION select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION @@ -61,8 +63,10 @@ config ARM64 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION select ARCH_KEEP_MEMBLOCK select ARCH_USE_CMPXCHG_LOCKREF + select ARCH_USE_GNU_PROPERTY select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS + select ARCH_USE_SYM_ANNOTATIONS select ARCH_SUPPORTS_MEMORY_FAILURE select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG) @@ -1584,6 +1588,48 @@ endmenu menu "ARMv8.5 architectural features" +config ARM64_BTI + bool "Branch Target Identification support" + default y + help + Branch Target Identification (part of the ARMv8.5 Extensions) + provides a mechanism to limit the set of locations to which computed + branch instructions such as BR or BLR can jump. + + To make use of BTI on CPUs that support it, say Y. + + BTI is intended to provide complementary protection to other control + flow integrity protection mechanisms, such as the Pointer + authentication mechanism provided as part of the ARMv8.3 Extensions. + For this reason, it does not make sense to enable this option without + also enabling support for pointer authentication. Thus, when + enabling this option you should also select ARM64_PTR_AUTH=y. + + Userspace binaries must also be specifically compiled to make use of + this mechanism. If you say N here or the hardware does not support + BTI, such binaries can still run, but you get no additional + enforcement of branch destinations. + +config ARM64_BTI_KERNEL + bool "Use Branch Target Identification for kernel" + default y + depends on ARM64_BTI + depends on ARM64_PTR_AUTH + depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI + # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697 + depends on !CC_IS_GCC || GCC_VERSION >= 100100 + depends on !(CC_IS_CLANG && GCOV_KERNEL) + depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) + help + Build the kernel with Branch Target Identification annotations + and enable enforcement of this for kernel code. When this option + is enabled and the system supports BTI all kernel code including + modular code must have BTI enabled. + +config CC_HAS_BRANCH_PROT_PAC_RET_BTI + # GCC 9 or later, clang 8 or later + def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti) + config ARM64_E0PD bool "Enable support for E0PD" default y diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index e48867c335d2..7dcd38be7dd0 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -70,7 +70,14 @@ branch-prot-flags-y += $(call cc-option,-mbranch-protection=none) ifeq ($(CONFIG_ARM64_PTR_AUTH),y) branch-prot-flags-$(CONFIG_CC_HAS_SIGN_RETURN_ADDRESS) := -msign-return-address=all +# We enable additional protection for leaf functions as there is some +# narrow potential for ROP protection benefits and no substantial +# performance impact has been observed. +ifeq ($(CONFIG_ARM64_BTI_KERNEL),y) +branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET_BTI) := -mbranch-protection=pac-ret+leaf+bti +else branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET) := -mbranch-protection=pac-ret+leaf +endif # -march=armv8.3-a enables the non-nops instructions for PAC, to avoid the # compiler to generate them and consequently to break the single image contract # we pass it only to the assembler. This option is utilized only in case of non diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 0bff325117b4..54d181177656 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -736,4 +736,54 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU .Lyield_out_\@ : .endm +/* + * This macro emits a program property note section identifying + * architecture features which require special handling, mainly for + * use in assembly files included in the VDSO. + */ + +#define NT_GNU_PROPERTY_TYPE_0 5 +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 + +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) +#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC (1U << 1) + +#ifdef CONFIG_ARM64_BTI_KERNEL +#define GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT \ + ((GNU_PROPERTY_AARCH64_FEATURE_1_BTI | \ + GNU_PROPERTY_AARCH64_FEATURE_1_PAC)) +#endif + +#ifdef GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT +.macro emit_aarch64_feature_1_and, feat=GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT + .pushsection .note.gnu.property, "a" + .align 3 + .long 2f - 1f + .long 6f - 3f + .long NT_GNU_PROPERTY_TYPE_0 +1: .string "GNU" +2: + .align 3 +3: .long GNU_PROPERTY_AARCH64_FEATURE_1_AND + .long 5f - 4f +4: + /* + * This is described with an array of char in the Linux API + * spec but the text and all other usage (including binutils, + * clang and GCC) treat this as a 32 bit value so no swizzling + * is required for big endian. + */ + .long \feat +5: + .align 3 +6: + .popsection +.endm + +#else +.macro emit_aarch64_feature_1_and, feat=0 +.endm + +#endif /* GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT */ + #endif /* __ASM_ASSEMBLER_H */ diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index c54c674e6c21..eacd0c74dfc7 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -62,7 +62,8 @@ #define ARM64_HAS_ADDRESS_AUTH 52 #define ARM64_HAS_GENERIC_AUTH 53 #define ARM64_HAS_32BIT_EL1 54 +#define ARM64_BTI 55 -#define ARM64_NCAPS 55 +#define ARM64_NCAPS 56 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 928814d35669..5d1f4ae42799 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -687,6 +687,11 @@ static inline bool system_has_prio_mask_debugging(void) system_uses_irq_prio_masking(); } +static inline bool system_supports_bti(void) +{ + return IS_ENABLED(CONFIG_ARM64_BTI) && cpus_have_const_cap(ARM64_BTI); +} + #define ARM64_BP_HARDEN_UNKNOWN -1 #define ARM64_BP_HARDEN_WA_NEEDED 0 #define ARM64_BP_HARDEN_NOT_REQUIRED 1 diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index b618017205a3..4f00d50585a4 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -114,7 +114,11 @@ #ifndef __ASSEMBLY__ +#include <uapi/linux/elf.h> #include <linux/bug.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/types.h> #include <asm/processor.h> /* for signal_minsigstksz, used by ARCH_DLINFO */ typedef unsigned long elf_greg_t; @@ -224,6 +228,52 @@ extern int aarch32_setup_additional_pages(struct linux_binprm *bprm, #endif /* CONFIG_COMPAT */ +struct arch_elf_state { + int flags; +}; + +#define ARM64_ELF_BTI (1 << 0) + +#define INIT_ARCH_ELF_STATE { \ + .flags = 0, \ +} + +static inline int arch_parse_elf_property(u32 type, const void *data, + size_t datasz, bool compat, + struct arch_elf_state *arch) +{ + /* No known properties for AArch32 yet */ + if (IS_ENABLED(CONFIG_COMPAT) && compat) + return 0; + + if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { + const u32 *p = data; + + if (datasz != sizeof(*p)) + return -ENOEXEC; + + if (system_supports_bti() && + (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) + arch->flags |= ARM64_ELF_BTI; + } + + return 0; +} + +static inline int arch_elf_pt_proc(void *ehdr, void *phdr, + struct file *f, bool is_interp, + struct arch_elf_state *state) +{ + return 0; +} + +static inline int arch_check_elf(void *ehdr, bool has_interp, + void *interp_ehdr, + struct arch_elf_state *state) +{ + return 0; +} + #endif /* !__ASSEMBLY__ */ #endif diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index 6a395a7e6707..035003acfa87 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -22,7 +22,7 @@ #define ESR_ELx_EC_PAC (0x09) /* EL2 and above */ /* Unallocated EC: 0x0A - 0x0B */ #define ESR_ELx_EC_CP14_64 (0x0C) -/* Unallocated EC: 0x0d */ +#define ESR_ELx_EC_BTI (0x0D) #define ESR_ELx_EC_ILL (0x0E) /* Unallocated EC: 0x0F - 0x10 */ #define ESR_ELx_EC_SVC32 (0x11) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 7a6e81ca23a8..7577a754d443 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -34,6 +34,7 @@ static inline u32 disr_to_esr(u64 disr) asmlinkage void enter_from_user_mode(void); void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); void do_undefinstr(struct pt_regs *regs); +void do_bti(struct pt_regs *regs); asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr); void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, struct pt_regs *regs); diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index 0f00265248b5..d683bcbf1e7c 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -94,6 +94,7 @@ #define KERNEL_HWCAP_BF16 __khwcap2_feature(BF16) #define KERNEL_HWCAP_DGH __khwcap2_feature(DGH) #define KERNEL_HWCAP_RNG __khwcap2_feature(RNG) +#define KERNEL_HWCAP_BTI __khwcap2_feature(BTI) /* * This yields a mask that user programs can use to figure out what diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index bb313dde58a4..0bc46149e491 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -39,13 +39,37 @@ enum aarch64_insn_encoding_class { * system instructions */ }; -enum aarch64_insn_hint_op { +enum aarch64_insn_hint_cr_op { AARCH64_INSN_HINT_NOP = 0x0 << 5, AARCH64_INSN_HINT_YIELD = 0x1 << 5, AARCH64_INSN_HINT_WFE = 0x2 << 5, AARCH64_INSN_HINT_WFI = 0x3 << 5, AARCH64_INSN_HINT_SEV = 0x4 << 5, AARCH64_INSN_HINT_SEVL = 0x5 << 5, + + AARCH64_INSN_HINT_XPACLRI = 0x07 << 5, + AARCH64_INSN_HINT_PACIA_1716 = 0x08 << 5, + AARCH64_INSN_HINT_PACIB_1716 = 0x0A << 5, + AARCH64_INSN_HINT_AUTIA_1716 = 0x0C << 5, + AARCH64_INSN_HINT_AUTIB_1716 = 0x0E << 5, + AARCH64_INSN_HINT_PACIAZ = 0x18 << 5, + AARCH64_INSN_HINT_PACIASP = 0x19 << 5, + AARCH64_INSN_HINT_PACIBZ = 0x1A << 5, + AARCH64_INSN_HINT_PACIBSP = 0x1B << 5, + AARCH64_INSN_HINT_AUTIAZ = 0x1C << 5, + AARCH64_INSN_HINT_AUTIASP = 0x1D << 5, + AARCH64_INSN_HINT_AUTIBZ = 0x1E << 5, + AARCH64_INSN_HINT_AUTIBSP = 0x1F << 5, + + AARCH64_INSN_HINT_ESB = 0x10 << 5, + AARCH64_INSN_HINT_PSB = 0x11 << 5, + AARCH64_INSN_HINT_TSB = 0x12 << 5, + AARCH64_INSN_HINT_CSDB = 0x14 << 5, + + AARCH64_INSN_HINT_BTI = 0x20 << 5, + AARCH64_INSN_HINT_BTIC = 0x22 << 5, + AARCH64_INSN_HINT_BTIJ = 0x24 << 5, + AARCH64_INSN_HINT_BTIJC = 0x26 << 5, }; enum aarch64_insn_imm_type { @@ -344,7 +368,7 @@ __AARCH64_INSN_FUNCS(msr_reg, 0xFFF00000, 0xD5100000) #undef __AARCH64_INSN_FUNCS -bool aarch64_insn_is_nop(u32 insn); +bool aarch64_insn_is_steppable_hint(u32 insn); bool aarch64_insn_is_branch_imm(u32 insn); static inline bool aarch64_insn_is_adr_adrp(u32 insn) @@ -370,7 +394,7 @@ u32 aarch64_insn_gen_comp_branch_imm(unsigned long pc, unsigned long addr, enum aarch64_insn_branch_type type); u32 aarch64_insn_gen_cond_branch_imm(unsigned long pc, unsigned long addr, enum aarch64_insn_condition cond); -u32 aarch64_insn_gen_hint(enum aarch64_insn_hint_op op); +u32 aarch64_insn_gen_hint(enum aarch64_insn_hint_cr_op op); u32 aarch64_insn_gen_nop(void); u32 aarch64_insn_gen_branch_reg(enum aarch64_insn_register reg, enum aarch64_insn_branch_type type); diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index a30b4eec7cb4..6ea53e6e8b26 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -507,10 +507,12 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, static __always_inline void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr) { - if (vcpu_mode_is_32bit(vcpu)) + if (vcpu_mode_is_32bit(vcpu)) { kvm_skip_instr32(vcpu, is_wide_instr); - else + } else { *vcpu_pc(vcpu) += 4; + *vcpu_cpsr(vcpu) &= ~PSR_BTYPE_MASK; + } /* advance the singlestep state machine */ *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; diff --git a/arch/arm64/include/asm/linkage.h b/arch/arm64/include/asm/linkage.h index ebee3113a62f..81fefd2a1d02 100644 --- a/arch/arm64/include/asm/linkage.h +++ b/arch/arm64/include/asm/linkage.h @@ -4,6 +4,52 @@ #define __ALIGN .align 2 #define __ALIGN_STR ".align 2" +#if defined(CONFIG_ARM64_BTI_KERNEL) && defined(__aarch64__) + +/* + * Since current versions of gas reject the BTI instruction unless we + * set the architecture version to v8.5 we use the hint instruction + * instead. + */ +#define BTI_C hint 34 ; +#define BTI_J hint 36 ; + +/* + * When using in-kernel BTI we need to ensure that PCS-conformant assembly + * functions have suitable annotations. Override SYM_FUNC_START to insert + * a BTI landing pad at the start of everything. + */ +#define SYM_FUNC_START(name) \ + SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \ + BTI_C + +#define SYM_FUNC_START_NOALIGN(name) \ + SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) \ + BTI_C + +#define SYM_FUNC_START_LOCAL(name) \ + SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) \ + BTI_C + +#define SYM_FUNC_START_LOCAL_NOALIGN(name) \ + SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) \ + BTI_C + +#define SYM_FUNC_START_WEAK(name) \ + SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) \ + BTI_C + +#define SYM_FUNC_START_WEAK_NOALIGN(name) \ + SYM_START(name, SYM_L_WEAK, SYM_A_NONE) \ + BTI_C + +#define SYM_INNER_LABEL(name, linkage) \ + .type name SYM_T_NONE ASM_NL \ + SYM_ENTRY(name, linkage, SYM_A_NONE) \ + BTI_J + +#endif + /* * Annotate a function as position independent, i.e., safe to be called before * the kernel virtual mapping is activated. diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h new file mode 100644 index 000000000000..081ec8de9ea6 --- /dev/null +++ b/arch/arm64/include/asm/mman.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MMAN_H__ +#define __ASM_MMAN_H__ + +#include <linux/compiler.h> +#include <linux/types.h> +#include <uapi/asm/mman.h> + +static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, + unsigned long pkey __always_unused) +{ + if (system_supports_bti() && (prot & PROT_BTI)) + return VM_ARM64_BTI; + + return 0; +} +#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) + +static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) +{ + return (vm_flags & VM_ARM64_BTI) ? __pgprot(PTE_GP) : __pgprot(0); +} +#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags) + +static inline bool arch_validate_prot(unsigned long prot, + unsigned long addr __always_unused) +{ + unsigned long supported = PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM; + + if (system_supports_bti()) + supported |= PROT_BTI; + + return (prot & ~supported) == 0; +} +#define arch_validate_prot(prot, addr) arch_validate_prot(prot, addr) + +#endif /* ! __ASM_MMAN_H__ */ diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h index 99315bdca0e6..9c91a8f93a0e 100644 --- a/arch/arm64/include/asm/pgtable-hwdef.h +++ b/arch/arm64/include/asm/pgtable-hwdef.h @@ -151,6 +151,7 @@ #define PTE_SHARED (_AT(pteval_t, 3) << 8) /* SH[1:0], inner shareable */ #define PTE_AF (_AT(pteval_t, 1) << 10) /* Access Flag */ #define PTE_NG (_AT(pteval_t, 1) << 11) /* nG */ +#define PTE_GP (_AT(pteval_t, 1) << 50) /* BTI guarded */ #define PTE_DBM (_AT(pteval_t, 1) << 51) /* Dirty Bit Management */ #define PTE_CONT (_AT(pteval_t, 1) << 52) /* Contiguous range */ #define PTE_PXN (_AT(pteval_t, 1) << 53) /* Privileged XN */ diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 1305e28225fc..2e7e0f452301 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -21,6 +21,7 @@ #ifndef __ASSEMBLY__ +#include <asm/cpufeature.h> #include <asm/pgtable-types.h> extern bool arm64_use_ng_mappings; @@ -31,6 +32,16 @@ extern bool arm64_use_ng_mappings; #define PTE_MAYBE_NG (arm64_use_ng_mappings ? PTE_NG : 0) #define PMD_MAYBE_NG (arm64_use_ng_mappings ? PMD_SECT_NG : 0) +/* + * If we have userspace only BTI we don't want to mark kernel pages + * guarded even if the system does support BTI. + */ +#ifdef CONFIG_ARM64_BTI_KERNEL +#define PTE_MAYBE_GP (system_supports_bti() ? PTE_GP : 0) +#else +#define PTE_MAYBE_GP 0 +#endif + #define PROT_DEFAULT (_PROT_DEFAULT | PTE_MAYBE_NG) #define PROT_SECT_DEFAULT (_PROT_SECT_DEFAULT | PMD_MAYBE_NG) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 5caff09c6a3a..e50e4dda90c2 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -661,7 +661,7 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) { const pteval_t mask = PTE_USER | PTE_PXN | PTE_UXN | PTE_RDONLY | - PTE_PROT_NONE | PTE_VALID | PTE_WRITE; + PTE_PROT_NONE | PTE_VALID | PTE_WRITE | PTE_GP; /* preserve the hardware dirty information */ if (pte_hw_dirty(pte)) pte = pte_mkdirty(pte); diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index bf57308fcd63..2172ec7594ba 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -35,6 +35,7 @@ #define GIC_PRIO_PSR_I_SET (1 << 4) /* Additional SPSR bits not exposed in the UABI */ + #define PSR_IL_BIT (1 << 20) /* AArch32-specific ptrace requests */ diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index efe368ee4996..463175f80341 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -559,6 +559,8 @@ #endif /* SCTLR_EL1 specific flags. */ +#define SCTLR_EL1_BT1 (BIT(36)) +#define SCTLR_EL1_BT0 (BIT(35)) #define SCTLR_EL1_UCI (BIT(26)) #define SCTLR_EL1_E0E (BIT(24)) #define SCTLR_EL1_SPAN (BIT(23)) @@ -679,6 +681,7 @@ #define ID_AA64PFR1_SSBS_PSTATE_NI 0 #define ID_AA64PFR1_SSBS_PSTATE_ONLY 1 #define ID_AA64PFR1_SSBS_PSTATE_INSNS 2 +#define ID_AA64PFR1_BT_BTI 0x1 /* id_aa64zfr0 */ #define ID_AA64ZFR0_F64MM_SHIFT 56 diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index 7752d93bb50f..2d6ba1c2592e 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -73,5 +73,6 @@ #define HWCAP2_BF16 (1 << 14) #define HWCAP2_DGH (1 << 15) #define HWCAP2_RNG (1 << 16) +#define HWCAP2_BTI (1 << 17) #endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/include/uapi/asm/mman.h b/arch/arm64/include/uapi/asm/mman.h new file mode 100644 index 000000000000..6fdd71eb644f --- /dev/null +++ b/arch/arm64/include/uapi/asm/mman.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI__ASM_MMAN_H +#define _UAPI__ASM_MMAN_H + +#include <asm-generic/mman.h> + +#define PROT_BTI 0x10 /* BTI guarded page */ + +#endif /* ! _UAPI__ASM_MMAN_H */ diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index d1bb5b69f1ce..42cbe34d95ce 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -46,6 +46,7 @@ #define PSR_I_BIT 0x00000080 #define PSR_A_BIT 0x00000100 #define PSR_D_BIT 0x00000200 +#define PSR_BTYPE_MASK 0x00000c00 #define PSR_SSBS_BIT 0x00001000 #define PSR_PAN_BIT 0x00400000 #define PSR_UAO_BIT 0x00800000 @@ -55,6 +56,8 @@ #define PSR_Z_BIT 0x40000000 #define PSR_N_BIT 0x80000000 +#define PSR_BTYPE_SHIFT 10 + /* * Groups of PSR bits */ @@ -63,6 +66,12 @@ #define PSR_x 0x0000ff00 /* Extension */ #define PSR_c 0x000000ff /* Control */ +/* Convenience names for the values of PSTATE.BTYPE */ +#define PSR_BTYPE_NONE (0b00 << PSR_BTYPE_SHIFT) +#define PSR_BTYPE_JC (0b01 << PSR_BTYPE_SHIFT) +#define PSR_BTYPE_C (0b10 << PSR_BTYPE_SHIFT) +#define PSR_BTYPE_J (0b11 << PSR_BTYPE_SHIFT) + /* syscall emulation path in ptrace */ #define PTRACE_SYSEMU 31 #define PTRACE_SYSEMU_SINGLESTEP 32 diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S index 38087b4c0432..4a18055b2ff9 100644 --- a/arch/arm64/kernel/cpu-reset.S +++ b/arch/arm64/kernel/cpu-reset.S @@ -29,7 +29,7 @@ * branch to what would be the reset vector. It must be executed with the * flat identity mapping. */ -ENTRY(__cpu_soft_restart) +SYM_CODE_START(__cpu_soft_restart) /* Clear sctlr_el1 flags. */ mrs x12, sctlr_el1 mov_q x13, SCTLR_ELx_FLAGS @@ -47,6 +47,6 @@ ENTRY(__cpu_soft_restart) mov x1, x3 // arg1 mov x2, x4 // arg2 br x8 -ENDPROC(__cpu_soft_restart) +SYM_CODE_END(__cpu_soft_restart) .popsection diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index b3202a99e559..4ae41670c2e6 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -241,6 +241,8 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = { ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_MPAMFRAC_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_RASFRAC_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SSBS_SHIFT, 4, ID_AA64PFR1_SSBS_PSTATE_NI), + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_BTI), + FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_BT_SHIFT, 4, 0), ARM64_FTR_END, }; @@ -1638,6 +1640,21 @@ static bool can_use_gic_priorities(const struct arm64_cpu_capabilities *entry, } #endif +#ifdef CONFIG_ARM64_BTI +static void bti_enable(const struct arm64_cpu_capabilities *__unused) +{ + /* + * Use of X16/X17 for tail-calls and trampolines that jump to + * function entry points using BR is a requirement for + * marking binaries with GNU_PROPERTY_AARCH64_FEATURE_1_BTI. + * So, be strict and forbid other BRs using other registers to + * jump onto a PACIxSP instruction: + */ + sysreg_clear_set(sctlr_el1, 0, SCTLR_EL1_BT0 | SCTLR_EL1_BT1); + isb(); +} +#endif /* CONFIG_ARM64_BTI */ + /* Internal helper functions to match cpu capability type */ static bool cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap) @@ -2020,6 +2037,23 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .min_field_value = 1, }, #endif +#ifdef CONFIG_ARM64_BTI + { + .desc = "Branch Target Identification", + .capability = ARM64_BTI, +#ifdef CONFIG_ARM64_BTI_KERNEL + .type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE, +#else + .type = ARM64_CPUCAP_SYSTEM_FEATURE, +#endif + .matches = has_cpuid_feature, + .cpu_enable = bti_enable, + .sys_reg = SYS_ID_AA64PFR1_EL1, + .field_pos = ID_AA64PFR1_BT_SHIFT, + .min_field_value = ID_AA64PFR1_BT_BTI, + .sign = FTR_UNSIGNED, + }, +#endif {}, }; @@ -2129,6 +2163,9 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { HWCAP_CAP(SYS_ID_AA64ZFR0_EL1, ID_AA64ZFR0_F64MM_SHIFT, FTR_UNSIGNED, ID_AA64ZFR0_F64MM, CAP_HWCAP, KERNEL_HWCAP_SVEF64MM), #endif HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, KERNEL_HWCAP_SSBS), +#ifdef CONFIG_ARM64_BTI + HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_BT_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_BT_BTI, CAP_HWCAP, KERNEL_HWCAP_BTI), +#endif #ifdef CONFIG_ARM64_PTR_AUTH HWCAP_MULTI_CAP(ptr_auth_hwcap_addr_matches, CAP_HWCAP, KERNEL_HWCAP_PACA), HWCAP_MULTI_CAP(ptr_auth_hwcap_gen_matches, CAP_HWCAP, KERNEL_HWCAP_PACG), diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index c1a257d93e90..86637466daa8 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -92,6 +92,7 @@ static const char *const hwcap_str[] = { "bf16", "dgh", "rng", + "bti", NULL }; diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 3fc71106cb2b..1192c4bb48df 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -5,7 +5,7 @@ #include <linux/linkage.h> -ENTRY(__efi_rt_asm_wrapper) +SYM_FUNC_START(__efi_rt_asm_wrapper) stp x29, x30, [sp, #-32]! mov x29, sp @@ -35,4 +35,4 @@ ENTRY(__efi_rt_asm_wrapper) b.ne 0f ret 0: b efi_handle_corrupted_x18 // tail call -ENDPROC(__efi_rt_asm_wrapper) +SYM_FUNC_END(__efi_rt_asm_wrapper) diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index bed09a866c2f..3dbdf9752b11 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -188,6 +188,14 @@ static void notrace el0_undef(struct pt_regs *regs) } NOKPROBE_SYMBOL(el0_undef); +static void notrace el0_bti(struct pt_regs *regs) +{ + user_exit_irqoff(); + local_daif_restore(DAIF_PROCCTX); + do_bti(regs); +} +NOKPROBE_SYMBOL(el0_bti); + static void notrace el0_inv(struct pt_regs *regs, unsigned long esr) { user_exit_irqoff(); @@ -255,6 +263,9 @@ asmlinkage void notrace el0_sync_handler(struct pt_regs *regs) case ESR_ELx_EC_UNKNOWN: el0_undef(regs); break; + case ESR_ELx_EC_BTI: + el0_bti(regs); + break; case ESR_ELx_EC_BREAKPT_LOW: case ESR_ELx_EC_SOFTSTP_LOW: case ESR_ELx_EC_WATCHPT_LOW: diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 0f24eae8f3cc..f880dd63ddc3 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -16,34 +16,34 @@ * * x0 - pointer to struct fpsimd_state */ -ENTRY(fpsimd_save_state) +SYM_FUNC_START(fpsimd_save_state) fpsimd_save x0, 8 ret -ENDPROC(fpsimd_save_state) +SYM_FUNC_END(fpsimd_save_state) /* * Load the FP registers. * * x0 - pointer to struct fpsimd_state */ -ENTRY(fpsimd_load_state) +SYM_FUNC_START(fpsimd_load_state) fpsimd_restore x0, 8 ret -ENDPROC(fpsimd_load_state) +SYM_FUNC_END(fpsimd_load_state) #ifdef CONFIG_ARM64_SVE -ENTRY(sve_save_state) +SYM_FUNC_START(sve_save_state) sve_save 0, x1, 2 ret -ENDPROC(sve_save_state) +SYM_FUNC_END(sve_save_state) -ENTRY(sve_load_state) +SYM_FUNC_START(sve_load_state) sve_load 0, x1, x2, 3, x4 ret -ENDPROC(sve_load_state) +SYM_FUNC_END(sve_load_state) -ENTRY(sve_get_vl) +SYM_FUNC_START(sve_get_vl) _sve_rdvl 0, 1 ret -ENDPROC(sve_get_vl) +SYM_FUNC_END(sve_get_vl) #endif /* CONFIG_ARM64_SVE */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index a9265fef914f..84cbc513c1e8 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -728,20 +728,9 @@ el0_error_naked: SYM_CODE_END(el0_error) /* - * Ok, we need to do extra processing, enter the slow path. - */ -work_pending: - mov x0, sp // 'regs' - bl do_notify_resume -#ifdef CONFIG_TRACE_IRQFLAGS - bl trace_hardirqs_on // enabled while in userspace -#endif - ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for single-step - b finish_ret_to_user -/* * "slow" syscall return path. */ -ret_to_user: +SYM_CODE_START_LOCAL(ret_to_user) disable_daif gic_prio_kentry_setup tmp=x3 ldr x1, [tsk, #TSK_TI_FLAGS] @@ -753,7 +742,19 @@ finish_ret_to_user: bl stackleak_erase #endif kernel_exit 0 -ENDPROC(ret_to_user) + +/* + * Ok, we need to do extra processing, enter the slow path. + */ +work_pending: + mov x0, sp // 'regs' + bl do_notify_resume +#ifdef CONFIG_TRACE_IRQFLAGS + bl trace_hardirqs_on // enabled while in userspace +#endif + ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for single-step + b finish_ret_to_user +SYM_CODE_END(ret_to_user) .popsection // .entry.text diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S index 6532105b3e32..8ccca660034e 100644 --- a/arch/arm64/kernel/hibernate-asm.S +++ b/arch/arm64/kernel/hibernate-asm.S @@ -65,7 +65,7 @@ * x5: physical address of a zero page that remains zero after resume */ .pushsection ".hibernate_exit.text", "ax" -ENTRY(swsusp_arch_suspend_exit) +SYM_CODE_START(swsusp_arch_suspend_exit) /* * We execute from ttbr0, change ttbr1 to our copied linear map tables * with a break-before-make via the zero page @@ -110,7 +110,7 @@ ENTRY(swsusp_arch_suspend_exit) cbz x24, 3f /* Do we need to re-initialise EL2? */ hvc #0 3: ret -ENDPROC(swsusp_arch_suspend_exit) +SYM_CODE_END(swsusp_arch_suspend_exit) /* * Restore the hyp stub. @@ -119,15 +119,15 @@ ENDPROC(swsusp_arch_suspend_exit) * * x24: The physical address of __hyp_stub_vectors */ -el1_sync: +SYM_CODE_START_LOCAL(el1_sync) msr vbar_el2, x24 eret -ENDPROC(el1_sync) +SYM_CODE_END(el1_sync) .macro invalid_vector label -\label: +SYM_CODE_START_LOCAL(\label) b \label -ENDPROC(\label) +SYM_CODE_END(\label) .endm invalid_vector el2_sync_invalid @@ -141,7 +141,7 @@ ENDPROC(\label) /* el2 vectors - switch el2 here while we restore the memory image. */ .align 11 -ENTRY(hibernate_el2_vectors) +SYM_CODE_START(hibernate_el2_vectors) ventry el2_sync_invalid // Synchronous EL2t ventry el2_irq_invalid // IRQ EL2t ventry el2_fiq_invalid // FIQ EL2t @@ -161,6 +161,6 @@ ENTRY(hibernate_el2_vectors) ventry el1_irq_invalid // IRQ 32-bit EL1 ventry el1_fiq_invalid // FIQ 32-bit EL1 ventry el1_error_invalid // Error 32-bit EL1 -END(hibernate_el2_vectors) +SYM_CODE_END(hibernate_el2_vectors) .popsection diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index e473ead806ed..160f5881a0b7 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -21,7 +21,7 @@ .align 11 -ENTRY(__hyp_stub_vectors) +SYM_CODE_START(__hyp_stub_vectors) ventry el2_sync_invalid // Synchronous EL2t ventry el2_irq_invalid // IRQ EL2t ventry el2_fiq_invalid // FIQ EL2t @@ -41,11 +41,11 @@ ENTRY(__hyp_stub_vectors) ventry el1_irq_invalid // IRQ 32-bit EL1 ventry el1_fiq_invalid // FIQ 32-bit EL1 ventry el1_error_invalid // Error 32-bit EL1 -ENDPROC(__hyp_stub_vectors) +SYM_CODE_END(__hyp_stub_vectors) .align 11 -el1_sync: +SYM_CODE_START_LOCAL(el1_sync) cmp x0, #HVC_SET_VECTORS b.ne 2f msr vbar_el2, x1 @@ -68,12 +68,12 @@ el1_sync: 9: mov x0, xzr eret -ENDPROC(el1_sync) +SYM_CODE_END(el1_sync) .macro invalid_vector label -\label: +SYM_CODE_START_LOCAL(\label) b \label -ENDPROC(\label) +SYM_CODE_END(\label) .endm invalid_vector el2_sync_invalid @@ -106,15 +106,15 @@ ENDPROC(\label) * initialisation entry point. */ -ENTRY(__hyp_set_vectors) +SYM_FUNC_START(__hyp_set_vectors) mov x1, x0 mov x0, #HVC_SET_VECTORS hvc #0 ret -ENDPROC(__hyp_set_vectors) +SYM_FUNC_END(__hyp_set_vectors) -ENTRY(__hyp_reset_vectors) +SYM_FUNC_START(__hyp_reset_vectors) mov x0, #HVC_RESET_VECTORS hvc #0 ret -ENDPROC(__hyp_reset_vectors) +SYM_FUNC_END(__hyp_reset_vectors) diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index cc2f3d901c91..684d871ae38d 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -51,21 +51,33 @@ enum aarch64_insn_encoding_class __kprobes aarch64_get_insn_class(u32 insn) return aarch64_insn_encoding_class[(insn >> 25) & 0xf]; } -/* NOP is an alias of HINT */ -bool __kprobes aarch64_insn_is_nop(u32 insn) +bool __kprobes aarch64_insn_is_steppable_hint(u32 insn) { if (!aarch64_insn_is_hint(insn)) return false; switch (insn & 0xFE0) { - case AARCH64_INSN_HINT_YIELD: - case AARCH64_INSN_HINT_WFE: - case AARCH64_INSN_HINT_WFI: - case AARCH64_INSN_HINT_SEV: - case AARCH64_INSN_HINT_SEVL: - return false; - default: + case AARCH64_INSN_HINT_XPACLRI: + case AARCH64_INSN_HINT_PACIA_1716: + case AARCH64_INSN_HINT_PACIB_1716: + case AARCH64_INSN_HINT_AUTIA_1716: + case AARCH64_INSN_HINT_AUTIB_1716: + case AARCH64_INSN_HINT_PACIAZ: + case AARCH64_INSN_HINT_PACIASP: + case AARCH64_INSN_HINT_PACIBZ: + case AARCH64_INSN_HINT_PACIBSP: + case AARCH64_INSN_HINT_AUTIAZ: + case AARCH64_INSN_HINT_AUTIASP: + case AARCH64_INSN_HINT_AUTIBZ: + case AARCH64_INSN_HINT_AUTIBSP: + case AARCH64_INSN_HINT_BTI: + case AARCH64_INSN_HINT_BTIC: + case AARCH64_INSN_HINT_BTIJ: + case AARCH64_INSN_HINT_BTIJC: + case AARCH64_INSN_HINT_NOP: return true; + default: + return false; } } @@ -574,7 +586,7 @@ u32 aarch64_insn_gen_cond_branch_imm(unsigned long pc, unsigned long addr, offset >> 2); } -u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_op op) +u32 __kprobes aarch64_insn_gen_hint(enum aarch64_insn_hint_cr_op op) { return aarch64_insn_get_hint_value() | op; } diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index b78fac9e546c..263d5fba4c8a 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -46,7 +46,7 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) * except for the NOP case. */ if (aarch64_insn_is_hint(insn)) - return aarch64_insn_is_nop(insn); + return aarch64_insn_is_steppable_hint(insn); return true; } diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S index 45dce03aaeaf..890ca72c5a51 100644 --- a/arch/arm64/kernel/probes/kprobes_trampoline.S +++ b/arch/arm64/kernel/probes/kprobes_trampoline.S @@ -61,7 +61,7 @@ ldp x28, x29, [sp, #S_X28] .endm -ENTRY(kretprobe_trampoline) +SYM_CODE_START(kretprobe_trampoline) sub sp, sp, #S_FRAME_SIZE save_all_base_regs @@ -79,4 +79,4 @@ ENTRY(kretprobe_trampoline) add sp, sp, #S_FRAME_SIZE ret -ENDPROC(kretprobe_trampoline) +SYM_CODE_END(kretprobe_trampoline) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 56be4cbf771f..eade7807e819 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -11,6 +11,7 @@ #include <linux/compat.h> #include <linux/efi.h> +#include <linux/elf.h> #include <linux/export.h> #include <linux/sched.h> #include <linux/sched/debug.h> @@ -18,6 +19,7 @@ #include <linux/sched/task_stack.h> #include <linux/kernel.h> #include <linux/lockdep.h> +#include <linux/mman.h> #include <linux/mm.h> #include <linux/stddef.h> #include <linux/sysctl.h> @@ -209,6 +211,15 @@ void machine_restart(char *cmd) while (1); } +#define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str +static const char *const btypes[] = { + bstr(NONE, "--"), + bstr( JC, "jc"), + bstr( C, "-c"), + bstr( J , "j-") +}; +#undef bstr + static void print_pstate(struct pt_regs *regs) { u64 pstate = regs->pstate; @@ -227,7 +238,10 @@ static void print_pstate(struct pt_regs *regs) pstate & PSR_AA32_I_BIT ? 'I' : 'i', pstate & PSR_AA32_F_BIT ? 'F' : 'f'); } else { - printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO)\n", + const char *btype_str = btypes[(pstate & PSR_BTYPE_MASK) >> + PSR_BTYPE_SHIFT]; + + printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO BTYPE=%s)\n", pstate, pstate & PSR_N_BIT ? 'N' : 'n', pstate & PSR_Z_BIT ? 'Z' : 'z', @@ -238,7 +252,8 @@ static void print_pstate(struct pt_regs *regs) pstate & PSR_I_BIT ? 'I' : 'i', pstate & PSR_F_BIT ? 'F' : 'f', pstate & PSR_PAN_BIT ? '+' : '-', - pstate & PSR_UAO_BIT ? '+' : '-'); + pstate & PSR_UAO_BIT ? '+' : '-', + btype_str); } } @@ -655,3 +670,25 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) if (system_capabilities_finalized()) preempt_schedule_irq(); } + +#ifdef CONFIG_BINFMT_ELF +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, + bool has_interp, bool is_interp) +{ + /* + * For dynamically linked executables the interpreter is + * responsible for setting PROT_BTI on everything except + * itself. + */ + if (is_interp != has_interp) + return prot; + + if (!(state->flags & ARM64_ELF_BTI)) + return prot; + + if (prot & PROT_EXEC) + prot |= PROT_BTI; + + return prot; +} +#endif diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index b3d3005d9515..585dd7f5c826 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1874,7 +1874,7 @@ void syscall_trace_exit(struct pt_regs *regs) */ #define SPSR_EL1_AARCH64_RES0_BITS \ (GENMASK_ULL(63, 32) | GENMASK_ULL(27, 25) | GENMASK_ULL(23, 22) | \ - GENMASK_ULL(20, 13) | GENMASK_ULL(11, 10) | GENMASK_ULL(5, 5)) + GENMASK_ULL(20, 13) | GENMASK_ULL(5, 5)) #define SPSR_EL1_AARCH32_RES0_BITS \ (GENMASK_ULL(63, 32) | GENMASK_ULL(22, 22) | GENMASK_ULL(20, 20)) diff --git a/arch/arm64/kernel/reloc_test_syms.S b/arch/arm64/kernel/reloc_test_syms.S index 16a34f188f26..c50f45fa29fa 100644 --- a/arch/arm64/kernel/reloc_test_syms.S +++ b/arch/arm64/kernel/reloc_test_syms.S @@ -5,81 +5,81 @@ #include <linux/linkage.h> -ENTRY(absolute_data64) +SYM_FUNC_START(absolute_data64) ldr x0, 0f ret 0: .quad sym64_abs -ENDPROC(absolute_data64) +SYM_FUNC_END(absolute_data64) -ENTRY(absolute_data32) +SYM_FUNC_START(absolute_data32) ldr w0, 0f ret 0: .long sym32_abs -ENDPROC(absolute_data32) +SYM_FUNC_END(absolute_data32) -ENTRY(absolute_data16) +SYM_FUNC_START(absolute_data16) adr x0, 0f ldrh w0, [x0] ret 0: .short sym16_abs, 0 -ENDPROC(absolute_data16) +SYM_FUNC_END(absolute_data16) -ENTRY(signed_movw) +SYM_FUNC_START(signed_movw) movz x0, #:abs_g2_s:sym64_abs movk x0, #:abs_g1_nc:sym64_abs movk x0, #:abs_g0_nc:sym64_abs ret -ENDPROC(signed_movw) +SYM_FUNC_END(signed_movw) -ENTRY(unsigned_movw) +SYM_FUNC_START(unsigned_movw) movz x0, #:abs_g3:sym64_abs movk x0, #:abs_g2_nc:sym64_abs movk x0, #:abs_g1_nc:sym64_abs movk x0, #:abs_g0_nc:sym64_abs ret -ENDPROC(unsigned_movw) +SYM_FUNC_END(unsigned_movw) .align 12 .space 0xff8 -ENTRY(relative_adrp) +SYM_FUNC_START(relative_adrp) adrp x0, sym64_rel add x0, x0, #:lo12:sym64_rel ret -ENDPROC(relative_adrp) +SYM_FUNC_END(relative_adrp) .align 12 .space 0xffc -ENTRY(relative_adrp_far) +SYM_FUNC_START(relative_adrp_far) adrp x0, memstart_addr add x0, x0, #:lo12:memstart_addr ret -ENDPROC(relative_adrp_far) +SYM_FUNC_END(relative_adrp_far) -ENTRY(relative_adr) +SYM_FUNC_START(relative_adr) adr x0, sym64_rel ret -ENDPROC(relative_adr) +SYM_FUNC_END(relative_adr) -ENTRY(relative_data64) +SYM_FUNC_START(relative_data64) adr x1, 0f ldr x0, [x1] add x0, x0, x1 ret 0: .quad sym64_rel - . -ENDPROC(relative_data64) +SYM_FUNC_END(relative_data64) -ENTRY(relative_data32) +SYM_FUNC_START(relative_data32) adr x1, 0f ldr w0, [x1] add x0, x0, x1 ret 0: .long sym64_rel - . -ENDPROC(relative_data32) +SYM_FUNC_END(relative_data32) -ENTRY(relative_data16) +SYM_FUNC_START(relative_data16) adr x1, 0f ldrsh w0, [x1] add x0, x0, x1 ret 0: .short sym64_rel - ., 0 -ENDPROC(relative_data16) +SYM_FUNC_END(relative_data16) diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S index c40ce496c78b..542d6edc6806 100644 --- a/arch/arm64/kernel/relocate_kernel.S +++ b/arch/arm64/kernel/relocate_kernel.S @@ -26,7 +26,7 @@ * control_code_page, a special page which has been set up to be preserved * during the copy operation. */ -ENTRY(arm64_relocate_new_kernel) +SYM_CODE_START(arm64_relocate_new_kernel) /* Setup the list loop variables. */ mov x18, x2 /* x18 = dtb address */ @@ -111,7 +111,7 @@ ENTRY(arm64_relocate_new_kernel) mov x3, xzr br x17 -ENDPROC(arm64_relocate_new_kernel) +SYM_CODE_END(arm64_relocate_new_kernel) .align 3 /* To keep the 64-bit values below naturally aligned. */ diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 339882db5a91..801d56cdf701 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -732,6 +732,22 @@ static void setup_return(struct pt_regs *regs, struct k_sigaction *ka, regs->regs[29] = (unsigned long)&user->next_frame->fp; regs->pc = (unsigned long)ka->sa.sa_handler; + /* + * Signal delivery is a (wacky) indirect function call in + * userspace, so simulate the same setting of BTYPE as a BLR + * <register containing the signal handler entry point>. + * Signal delivery to a location in a PROT_BTI guarded page + * that is not a function entry point will now trigger a + * SIGILL in userspace. + * + * If the signal handler entry point is not in a PROT_BTI + * guarded page, this is harmless. + */ + if (system_supports_bti()) { + regs->pstate &= ~PSR_BTYPE_MASK; + regs->pstate |= PSR_BTYPE_C; + } + if (ka->sa.sa_flags & SA_RESTORER) sigtramp = ka->sa.sa_restorer; else diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index 56b1fe9bfaa0..ba40d57757d6 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -62,7 +62,7 @@ * * x0 = struct sleep_stack_data area */ -ENTRY(__cpu_suspend_enter) +SYM_FUNC_START(__cpu_suspend_enter) stp x29, lr, [x0, #SLEEP_STACK_DATA_CALLEE_REGS] stp x19, x20, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+16] stp x21, x22, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+32] @@ -95,10 +95,10 @@ ENTRY(__cpu_suspend_enter) ldp x29, lr, [sp], #16 mov x0, #1 ret -ENDPROC(__cpu_suspend_enter) +SYM_FUNC_END(__cpu_suspend_enter) .pushsection ".idmap.text", "awx" -ENTRY(cpu_resume) +SYM_CODE_START(cpu_resume) bl el2_setup // if in EL2 drop to EL1 cleanly bl __cpu_setup /* enable the MMU early - so we can access sleep_save_stash by va */ @@ -106,11 +106,11 @@ ENTRY(cpu_resume) bl __enable_mmu ldr x8, =_cpu_resume br x8 -ENDPROC(cpu_resume) +SYM_CODE_END(cpu_resume) .ltorg .popsection -ENTRY(_cpu_resume) +SYM_FUNC_START(_cpu_resume) mrs x1, mpidr_el1 adr_l x8, mpidr_hash // x8 = struct mpidr_hash virt address @@ -146,4 +146,4 @@ ENTRY(_cpu_resume) ldp x29, lr, [x29] mov x0, #0 ret -ENDPROC(_cpu_resume) +SYM_FUNC_END(_cpu_resume) diff --git a/arch/arm64/kernel/smccc-call.S b/arch/arm64/kernel/smccc-call.S index 54655273d1e0..1f93809528a4 100644 --- a/arch/arm64/kernel/smccc-call.S +++ b/arch/arm64/kernel/smccc-call.S @@ -30,9 +30,9 @@ * unsigned long a6, unsigned long a7, struct arm_smccc_res *res, * struct arm_smccc_quirk *quirk) */ -ENTRY(__arm_smccc_smc) +SYM_FUNC_START(__arm_smccc_smc) SMCCC smc -ENDPROC(__arm_smccc_smc) +SYM_FUNC_END(__arm_smccc_smc) EXPORT_SYMBOL(__arm_smccc_smc) /* @@ -41,7 +41,7 @@ EXPORT_SYMBOL(__arm_smccc_smc) * unsigned long a6, unsigned long a7, struct arm_smccc_res *res, * struct arm_smccc_quirk *quirk) */ -ENTRY(__arm_smccc_hvc) +SYM_FUNC_START(__arm_smccc_hvc) SMCCC hvc -ENDPROC(__arm_smccc_hvc) +SYM_FUNC_END(__arm_smccc_hvc) EXPORT_SYMBOL(__arm_smccc_hvc) diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index a12c0c88d345..5f5b868292f5 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -98,6 +98,24 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, regs->orig_x0 = regs->regs[0]; regs->syscallno = scno; + /* + * BTI note: + * The architecture does not guarantee that SPSR.BTYPE is zero + * on taking an SVC, so we could return to userspace with a + * non-zero BTYPE after the syscall. + * + * This shouldn't matter except when userspace is explicitly + * doing something stupid, such as setting PROT_BTI on a page + * that lacks conforming BTI/PACIxSP instructions, falling + * through from one executable page to another with differing + * PROT_BTI, or messing with BTYPE via ptrace: in such cases, + * userspace should not be surprised if a SIGILL occurs on + * syscall return. + * + * So, don't touch regs->pstate & PSR_BTYPE_MASK here. + * (Similarly for HVC and SMC elsewhere.) + */ + cortex_a76_erratum_1463225_svc_handler(); local_daif_restore(DAIF_PROCCTX); user_exit(); diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 8408e8670f2e..f8663308ac03 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -272,6 +272,61 @@ void arm64_notify_die(const char *str, struct pt_regs *regs, } } +#ifdef CONFIG_COMPAT +#define PSTATE_IT_1_0_SHIFT 25 +#define PSTATE_IT_1_0_MASK (0x3 << PSTATE_IT_1_0_SHIFT) +#define PSTATE_IT_7_2_SHIFT 10 +#define PSTATE_IT_7_2_MASK (0x3f << PSTATE_IT_7_2_SHIFT) + +static u32 compat_get_it_state(struct pt_regs *regs) +{ + u32 it, pstate = regs->pstate; + + it = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT; + it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2; + + return it; +} + +static void compat_set_it_state(struct pt_regs *regs, u32 it) +{ + u32 pstate_it; + + pstate_it = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK; + pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK; + + regs->pstate &= ~PSR_AA32_IT_MASK; + regs->pstate |= pstate_it; +} + +static void advance_itstate(struct pt_regs *regs) +{ + u32 it; + + /* ARM mode */ + if (!(regs->pstate & PSR_AA32_T_BIT) || + !(regs->pstate & PSR_AA32_IT_MASK)) + return; + + it = compat_get_it_state(regs); + + /* + * If this is the last instruction of the block, wipe the IT + * state. Otherwise advance it. + */ + if (!(it & 7)) + it = 0; + else + it = (it & 0xe0) | ((it << 1) & 0x1f); + + compat_set_it_state(regs, it); +} +#else +static void advance_itstate(struct pt_regs *regs) +{ +} +#endif + void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) { regs->pc += size; @@ -282,6 +337,11 @@ void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) */ if (user_mode(regs)) user_fastforward_single_step(current); + + if (compat_user_mode(regs)) + advance_itstate(regs); + else + regs->pstate &= ~PSR_BTYPE_MASK; } static LIST_HEAD(undef_hook); @@ -411,6 +471,13 @@ void do_undefinstr(struct pt_regs *regs) } NOKPROBE_SYMBOL(do_undefinstr); +void do_bti(struct pt_regs *regs) +{ + BUG_ON(!user_mode(regs)); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); +} +NOKPROBE_SYMBOL(do_bti); + #define __user_cache_maint(insn, address, res) \ if (address >= user_addr_max()) { \ res = -EFAULT; \ @@ -566,34 +633,7 @@ static const struct sys64_hook sys64_hooks[] = { {}, }; - #ifdef CONFIG_COMPAT -#define PSTATE_IT_1_0_SHIFT 25 -#define PSTATE_IT_1_0_MASK (0x3 << PSTATE_IT_1_0_SHIFT) -#define PSTATE_IT_7_2_SHIFT 10 -#define PSTATE_IT_7_2_MASK (0x3f << PSTATE_IT_7_2_SHIFT) - -static u32 compat_get_it_state(struct pt_regs *regs) -{ - u32 it, pstate = regs->pstate; - - it = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT; - it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2; - - return it; -} - -static void compat_set_it_state(struct pt_regs *regs, u32 it) -{ - u32 pstate_it; - - pstate_it = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK; - pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK; - - regs->pstate &= ~PSR_AA32_IT_MASK; - regs->pstate |= pstate_it; -} - static bool cp15_cond_valid(unsigned int esr, struct pt_regs *regs) { int cond; @@ -614,42 +654,12 @@ static bool cp15_cond_valid(unsigned int esr, struct pt_regs *regs) return aarch32_opcode_cond_checks[cond](regs->pstate); } -static void advance_itstate(struct pt_regs *regs) -{ - u32 it; - - /* ARM mode */ - if (!(regs->pstate & PSR_AA32_T_BIT) || - !(regs->pstate & PSR_AA32_IT_MASK)) - return; - - it = compat_get_it_state(regs); - - /* - * If this is the last instruction of the block, wipe the IT - * state. Otherwise advance it. - */ - if (!(it & 7)) - it = 0; - else - it = (it & 0xe0) | ((it << 1) & 0x1f); - - compat_set_it_state(regs, it); -} - -static void arm64_compat_skip_faulting_instruction(struct pt_regs *regs, - unsigned int sz) -{ - advance_itstate(regs); - arm64_skip_faulting_instruction(regs, sz); -} - static void compat_cntfrq_read_handler(unsigned int esr, struct pt_regs *regs) { int reg = (esr & ESR_ELx_CP15_32_ISS_RT_MASK) >> ESR_ELx_CP15_32_ISS_RT_SHIFT; pt_regs_write_reg(regs, reg, arch_timer_get_rate()); - arm64_compat_skip_faulting_instruction(regs, 4); + arm64_skip_faulting_instruction(regs, 4); } static const struct sys64_hook cp15_32_hooks[] = { @@ -669,7 +679,7 @@ static void compat_cntvct_read_handler(unsigned int esr, struct pt_regs *regs) pt_regs_write_reg(regs, rt, lower_32_bits(val)); pt_regs_write_reg(regs, rt2, upper_32_bits(val)); - arm64_compat_skip_faulting_instruction(regs, 4); + arm64_skip_faulting_instruction(regs, 4); } static const struct sys64_hook cp15_64_hooks[] = { @@ -690,7 +700,7 @@ void do_cp15instr(unsigned int esr, struct pt_regs *regs) * There is no T16 variant of a CP access, so we * always advance PC by 4 bytes. */ - arm64_compat_skip_faulting_instruction(regs, 4); + arm64_skip_faulting_instruction(regs, 4); return; } @@ -753,6 +763,7 @@ static const char *esr_class_str[] = { [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS", [ESR_ELx_EC_PAC] = "PAC", [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC", + [ESR_ELx_EC_BTI] = "BTI", [ESR_ELx_EC_ILL] = "PSTATE.IL", [ESR_ELx_EC_SVC32] = "SVC (AArch32)", [ESR_ELx_EC_HVC32] = "HVC (AArch32)", diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index f3eea5e20a41..d51a898fd60f 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -136,6 +136,7 @@ static int __setup_additional_pages(enum vdso_abi abi, int uses_interp) { unsigned long vdso_base, vdso_text_len, vdso_mapping_len; + unsigned long gp_flags = 0; void *ret; vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT; @@ -154,10 +155,13 @@ static int __setup_additional_pages(enum vdso_abi abi, if (IS_ERR(ret)) goto up_fail; + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) && system_supports_bti()) + gp_flags = VM_ARM64_BTI; + vdso_base += PAGE_SIZE; mm->context.vdso = (void *)vdso_base; ret = _install_special_mapping(mm, vdso_base, vdso_text_len, - VM_READ|VM_EXEC| + VM_READ|VM_EXEC|gp_flags| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, vdso_info[abi].cm); if (IS_ERR(ret)) diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 95e9e444ca93..fccd67d07c8c 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -17,12 +17,14 @@ obj-vdso := vgettimeofday.o note.o sigreturn.o targets := $(obj-vdso) vdso.so vdso.so.dbg obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) +btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti + # -Bsymbolic has been added for consistency with arm, the compat vDSO and # potential future proofing if we end up with internal calls to the exported # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so # preparation in build-time C")). ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \ - -Bsymbolic --eh-frame-hdr --build-id -n -T + -Bsymbolic --eh-frame-hdr --build-id -n $(btildflags-y) -T ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 ccflags-y += -DDISABLE_BRANCH_PROFILING diff --git a/arch/arm64/kernel/vdso/note.S b/arch/arm64/kernel/vdso/note.S index 0ce6ec75a525..3d4e82290c80 100644 --- a/arch/arm64/kernel/vdso/note.S +++ b/arch/arm64/kernel/vdso/note.S @@ -12,9 +12,12 @@ #include <linux/version.h> #include <linux/elfnote.h> #include <linux/build-salt.h> +#include <asm/assembler.h> ELFNOTE_START(Linux, 0, "a") .long LINUX_VERSION_CODE ELFNOTE_END BUILD_SALT + +emit_aarch64_feature_1_and diff --git a/arch/arm64/kernel/vdso/sigreturn.S b/arch/arm64/kernel/vdso/sigreturn.S index 12324863d5c2..620a3ef837b7 100644 --- a/arch/arm64/kernel/vdso/sigreturn.S +++ b/arch/arm64/kernel/vdso/sigreturn.S @@ -1,7 +1,11 @@ /* SPDX-License-Identifier: GPL-2.0-only */ /* * Sigreturn trampoline for returning from a signal when the SA_RESTORER - * flag is not set. + * flag is not set. It serves primarily as a hall of shame for crappy + * unwinders and features an exciting but mysterious NOP instruction. + * + * It's also fragile as hell, so please think twice before changing anything + * in here. * * Copyright (C) 2012 ARM Limited * @@ -9,18 +13,54 @@ */ #include <linux/linkage.h> +#include <asm/assembler.h> #include <asm/unistd.h> .text - nop -SYM_FUNC_START(__kernel_rt_sigreturn) +/* Ensure that the mysterious NOP can be associated with a function. */ .cfi_startproc + +/* + * .cfi_signal_frame causes the corresponding Frame Description Entry in the + * .eh_frame section to be annotated as a signal frame. This allows DWARF + * unwinders (e.g. libstdc++) to implement _Unwind_GetIPInfo(), which permits + * unwinding out of the signal trampoline without the need for the mysterious + * NOP. + */ .cfi_signal_frame - .cfi_def_cfa x29, 0 - .cfi_offset x29, 0 * 8 - .cfi_offset x30, 1 * 8 + +/* + * Tell the unwinder where to locate the frame record linking back to the + * interrupted context. We don't provide unwind info for registers other + * than the frame pointer and the link register here; in practice, this + * is sufficient for unwinding in C/C++ based runtimes and the values in + * the sigcontext may have been modified by this point anyway. Debuggers + * already have baked-in strategies for attempting to unwind out of signals. + */ + .cfi_def_cfa x29, 0 + .cfi_offset x29, 0 * 8 + .cfi_offset x30, 1 * 8 + +/* + * This mysterious NOP is required for some unwinders (e.g. libc++) that + * unconditionally subtract one from the result of _Unwind_GetIP() in order to + * identify the calling function. + * Hack borrowed from arch/powerpc/kernel/vdso64/sigtramp.S. + */ + nop // Mysterious NOP + +/* + * GDB relies on being able to identify the sigreturn instruction sequence to + * unwind from signal handlers. We cannot, therefore, use SYM_FUNC_START() + * here, as it will emit a BTI C instruction and break the unwinder. Thankfully, + * this function is only ever called from a RET and so omitting the landing pad + * is perfectly fine. + */ +SYM_CODE_START(__kernel_rt_sigreturn) mov x8, #__NR_rt_sigreturn svc #0 .cfi_endproc -SYM_FUNC_END(__kernel_rt_sigreturn) +SYM_CODE_END(__kernel_rt_sigreturn) + +emit_aarch64_feature_1_and diff --git a/arch/arm64/kernel/vdso/vdso.S b/arch/arm64/kernel/vdso/vdso.S index d1414fee5274..c4b1990bf2be 100644 --- a/arch/arm64/kernel/vdso/vdso.S +++ b/arch/arm64/kernel/vdso/vdso.S @@ -8,6 +8,7 @@ #include <linux/init.h> #include <linux/linkage.h> #include <linux/const.h> +#include <asm/assembler.h> #include <asm/page.h> .globl vdso_start, vdso_end @@ -19,3 +20,5 @@ vdso_start: vdso_end: .previous + +emit_aarch64_feature_1_and diff --git a/arch/arm64/kernel/vdso32/sigreturn.S b/arch/arm64/kernel/vdso32/sigreturn.S index 620524969696..b0091064c3d6 100644 --- a/arch/arm64/kernel/vdso32/sigreturn.S +++ b/arch/arm64/kernel/vdso32/sigreturn.S @@ -3,6 +3,9 @@ * This file provides both A32 and T32 versions, in accordance with the * arm sigreturn code. * + * Please read the comments in arch/arm64/kernel/vdso/sigreturn.S to + * understand some of the craziness in here. + * * Copyright (C) 2018 ARM Limited */ @@ -17,39 +20,39 @@ .save {r0-r15} .pad #COMPAT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_sigreturn_arm) +SYM_CODE_START(__kernel_sigreturn_arm) mov r7, #__NR_compat_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_sigreturn_arm) +SYM_CODE_END(__kernel_sigreturn_arm) .fnstart .save {r0-r15} .pad #COMPAT_RT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_rt_sigreturn_arm) +SYM_CODE_START(__kernel_rt_sigreturn_arm) mov r7, #__NR_compat_rt_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_rt_sigreturn_arm) +SYM_CODE_END(__kernel_rt_sigreturn_arm) .thumb .fnstart .save {r0-r15} .pad #COMPAT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_sigreturn_thumb) +SYM_CODE_START(__kernel_sigreturn_thumb) mov r7, #__NR_compat_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_sigreturn_thumb) +SYM_CODE_END(__kernel_sigreturn_thumb) .fnstart .save {r0-r15} .pad #COMPAT_RT_SIGFRAME_REGS_OFFSET nop -SYM_FUNC_START(__kernel_rt_sigreturn_thumb) +SYM_CODE_START(__kernel_rt_sigreturn_thumb) mov r7, #__NR_compat_rt_sigreturn svc #0 .fnend -SYM_FUNC_END(__kernel_rt_sigreturn_thumb) +SYM_CODE_END(__kernel_rt_sigreturn_thumb) diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c index 860c00ec8bd3..78163b7a7dde 100644 --- a/arch/arm64/mm/dump.c +++ b/arch/arm64/mm/dump.c @@ -146,6 +146,11 @@ static const struct prot_bits pte_bits[] = { .set = "UXN", .clear = " ", }, { + .mask = PTE_GP, + .val = PTE_GP, + .set = "GP", + .clear = " ", + }, { .mask = PTE_ATTRINDX_MASK, .val = PTE_ATTRINDX(MT_DEVICE_nGnRnE), .set = "DEVICE/nGnRnE", diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index a374e4f51a62..c299b73dd5e4 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -610,6 +610,22 @@ core_initcall(map_entry_trampoline); #endif /* + * Open coded check for BTI, only for use to determine configuration + * for early mappings for before the cpufeature code has run. + */ +static bool arm64_early_this_cpu_has_bti(void) +{ + u64 pfr1; + + if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + return false; + + pfr1 = read_sysreg_s(SYS_ID_AA64PFR1_EL1); + return cpuid_feature_extract_unsigned_field(pfr1, + ID_AA64PFR1_BT_SHIFT); +} + +/* * Create fine-grained mappings for the kernel. */ static void __init map_kernel(pgd_t *pgdp) @@ -625,6 +641,14 @@ static void __init map_kernel(pgd_t *pgdp) pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; /* + * If we have a CPU that supports BTI and a kernel built for + * BTI then mark the kernel executable text as guarded pages + * now so we don't have to rewrite the page tables later. + */ + if (arm64_early_this_cpu_has_bti()) + text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); + + /* * Only rodata will be remapped with different permissions later on, * all other segments are allowed to use contiguous mappings. */ diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 250c49008d73..bde08090b838 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -126,13 +126,13 @@ int set_memory_nx(unsigned long addr, int numpages) { return change_memory_common(addr, numpages, __pgprot(PTE_PXN), - __pgprot(0)); + __pgprot(PTE_MAYBE_GP)); } int set_memory_x(unsigned long addr, int numpages) { return change_memory_common(addr, numpages, - __pgprot(0), + __pgprot(PTE_MAYBE_GP), __pgprot(PTE_PXN)); } diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h index 923ae7ff68c8..cc0cf0f5c7c3 100644 --- a/arch/arm64/net/bpf_jit.h +++ b/arch/arm64/net/bpf_jit.h @@ -211,4 +211,12 @@ /* Rn & imm; set condition flags */ #define A64_TST_I(sf, Rn, imm) A64_ANDS_I(sf, A64_ZR, Rn, imm) +/* HINTs */ +#define A64_HINT(x) aarch64_insn_gen_hint(x) + +/* BTI */ +#define A64_BTI_C A64_HINT(AARCH64_INSN_HINT_BTIC) +#define A64_BTI_J A64_HINT(AARCH64_INSN_HINT_BTIJ) +#define A64_BTI_JC A64_HINT(AARCH64_INSN_HINT_BTIJC) + #endif /* _BPF_JIT_H */ diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 561a2fea9cdd..3cb25b43b368 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -177,7 +177,11 @@ static bool is_addsub_imm(u32 imm) #define STACK_ALIGN(sz) (((sz) + 15) & ~15) /* Tail call offset to jump into */ +#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) +#define PROLOGUE_OFFSET 8 +#else #define PROLOGUE_OFFSET 7 +#endif static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) { @@ -214,6 +218,10 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) * */ + /* BTI landing pad */ + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + emit(A64_BTI_C, ctx); + /* Save FP and LR registers to stay align with ARM64 AAPCS */ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); emit(A64_MOV(1, A64_FP, A64_SP), ctx); @@ -236,6 +244,10 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) cur_offset, PROLOGUE_OFFSET); return -1; } + + /* BTI landing pad for the tail call, done with a BR */ + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + emit(A64_BTI_J, ctx); } ctx->stack_size = STACK_ALIGN(prog->aux->stack_depth); diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1197b5596d5a..e90d16da9685 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -91,6 +91,7 @@ config X86 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS + select ARCH_USE_SYM_ANNOTATIONS select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 select ARCH_WANTS_DYNAMIC_TASK_STRUCT diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 2e74690b028a..f909d3ce36e6 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -99,15 +99,6 @@ config DEBUG_WX If in doubt, say "Y". -config DOUBLEFAULT - default y - bool "Enable doublefault exception handler" if EXPERT && X86_32 - ---help--- - This option allows trapping of rare doublefault exceptions that - would otherwise cause a system to silently reboot. Disabling this - option saves about 4k and might cause you much additional grey - hair. - config DEBUG_TLBFLUSH bool "Set upper limit of TLB entries to flush one-by-one" depends on DEBUG_KERNEL diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index b67bae7091d7..5c9c7eee6325 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1536,7 +1536,6 @@ SYM_CODE_START(debug) jmp common_exception SYM_CODE_END(debug) -#ifdef CONFIG_DOUBLEFAULT SYM_CODE_START(double_fault) 1: /* @@ -1576,7 +1575,6 @@ SYM_CODE_START(double_fault) hlt jmp 1b SYM_CODE_END(double_fault) -#endif /* * NMI is doubly nasty. It can happen on the first instruction of diff --git a/arch/x86/include/asm/doublefault.h b/arch/x86/include/asm/doublefault.h index af9a14ac8962..54a6e4a2e132 100644 --- a/arch/x86/include/asm/doublefault.h +++ b/arch/x86/include/asm/doublefault.h @@ -2,7 +2,7 @@ #ifndef _ASM_X86_DOUBLEFAULT_H #define _ASM_X86_DOUBLEFAULT_H -#if defined(CONFIG_X86_32) && defined(CONFIG_DOUBLEFAULT) +#ifdef CONFIG_X86_32 extern void doublefault_init_cpu_tss(void); #else static inline void doublefault_init_cpu_tss(void) diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index c26a7e1d8a2c..70bd0f356e5d 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -69,9 +69,7 @@ dotraplinkage void do_overflow(struct pt_regs *regs, long error_code); dotraplinkage void do_bounds(struct pt_regs *regs, long error_code); dotraplinkage void do_invalid_op(struct pt_regs *regs, long error_code); dotraplinkage void do_device_not_available(struct pt_regs *regs, long error_code); -#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT) dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2); -#endif dotraplinkage void do_coprocessor_segment_overrun(struct pt_regs *regs, long error_code); dotraplinkage void do_invalid_TSS(struct pt_regs *regs, long error_code); dotraplinkage void do_segment_not_present(struct pt_regs *regs, long error_code); diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index ba89cabe5fcf..2a7c3afa62e2 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -102,9 +102,7 @@ obj-$(CONFIG_KEXEC_FILE) += kexec-bzimage64.o obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o obj-y += kprobes/ obj-$(CONFIG_MODULES) += module.o -ifeq ($(CONFIG_X86_32),y) -obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o -endif +obj-$(CONFIG_X86_32) += doublefault_32.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_VM86) += vm86_32.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index 8e3a8fedfa4d..722fd712e1cf 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -87,7 +87,6 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info) { -#ifdef CONFIG_DOUBLEFAULT struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id()); struct doublefault_stack *ss = &cea->doublefault_stack; @@ -103,9 +102,6 @@ static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info) info->next_sp = (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp); return true; -#else - return false; -#endif } diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index d54cffdc7cac..e85561fc0dc8 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -326,7 +326,6 @@ __visible void __noreturn handle_stack_overflow(const char *message, } #endif -#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT) /* * Runs on an IST stack for x86_64 and on a special task stack for x86_32. * @@ -450,7 +449,6 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsign die("double fault", regs, error_code); panic("Machine halted."); } -#endif dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) { diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 56f9189bbadb..5199d8a1daf1 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -17,7 +17,7 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(struct exception_stacks, exception_stacks); DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks); #endif -#if defined(CONFIG_X86_32) && defined(CONFIG_DOUBLEFAULT) +#ifdef CONFIG_X86_32 DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack); #endif @@ -114,12 +114,10 @@ static void __init percpu_setup_exception_stacks(unsigned int cpu) #else static inline void percpu_setup_exception_stacks(unsigned int cpu) { -#ifdef CONFIG_DOUBLEFAULT struct cpu_entry_area *cea = get_cpu_entry_area(cpu); cea_map_percpu_pages(&cea->doublefault_stack, &per_cpu(doublefault_stack, cpu), 1, PAGE_KERNEL); -#endif } #endif diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt index 62dc4f577ba1..2358368319b8 100644 --- a/fs/Kconfig.binfmt +++ b/fs/Kconfig.binfmt @@ -36,6 +36,12 @@ config COMPAT_BINFMT_ELF config ARCH_BINFMT_ELF_STATE bool +config ARCH_HAVE_ELF_PROT + bool + +config ARCH_USE_GNU_PROPERTY + bool + config BINFMT_ELF_FDPIC bool "Kernel support for FDPIC ELF binaries" default y if !BINFMT_ELF diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 13f25e241ac4..4adb963cdb83 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -40,12 +40,18 @@ #include <linux/sched/coredump.h> #include <linux/sched/task_stack.h> #include <linux/sched/cputime.h> +#include <linux/sizes.h> +#include <linux/types.h> #include <linux/cred.h> #include <linux/dax.h> #include <linux/uaccess.h> #include <asm/param.h> #include <asm/page.h> +#ifndef ELF_COMPAT +#define ELF_COMPAT 0 +#endif + #ifndef user_long_t #define user_long_t long #endif @@ -539,7 +545,8 @@ static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp, #endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */ -static inline int make_prot(u32 p_flags) +static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state, + bool has_interp, bool is_interp) { int prot = 0; @@ -549,7 +556,8 @@ static inline int make_prot(u32 p_flags) prot |= PROT_WRITE; if (p_flags & PF_X) prot |= PROT_EXEC; - return prot; + + return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp); } /* This is much more generalized than the library routine read function, @@ -559,7 +567,8 @@ static inline int make_prot(u32 p_flags) static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, struct file *interpreter, - unsigned long no_base, struct elf_phdr *interp_elf_phdata) + unsigned long no_base, struct elf_phdr *interp_elf_phdata, + struct arch_elf_state *arch_state) { struct elf_phdr *eppnt; unsigned long load_addr = 0; @@ -591,7 +600,8 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) { if (eppnt->p_type == PT_LOAD) { int elf_type = MAP_PRIVATE | MAP_DENYWRITE; - int elf_prot = make_prot(eppnt->p_flags); + int elf_prot = make_prot(eppnt->p_flags, arch_state, + true, true); unsigned long vaddr = 0; unsigned long k, map_addr; @@ -682,6 +692,111 @@ out: * libraries. There is no binary dependent code anywhere else. */ +static int parse_elf_property(const char *data, size_t *off, size_t datasz, + struct arch_elf_state *arch, + bool have_prev_type, u32 *prev_type) +{ + size_t o, step; + const struct gnu_property *pr; + int ret; + + if (*off == datasz) + return -ENOENT; + + if (WARN_ON_ONCE(*off > datasz || *off % ELF_GNU_PROPERTY_ALIGN)) + return -EIO; + o = *off; + datasz -= *off; + + if (datasz < sizeof(*pr)) + return -ENOEXEC; + pr = (const struct gnu_property *)(data + o); + o += sizeof(*pr); + datasz -= sizeof(*pr); + + if (pr->pr_datasz > datasz) + return -ENOEXEC; + + WARN_ON_ONCE(o % ELF_GNU_PROPERTY_ALIGN); + step = round_up(pr->pr_datasz, ELF_GNU_PROPERTY_ALIGN); + if (step > datasz) + return -ENOEXEC; + + /* Properties are supposed to be unique and sorted on pr_type: */ + if (have_prev_type && pr->pr_type <= *prev_type) + return -ENOEXEC; + *prev_type = pr->pr_type; + + ret = arch_parse_elf_property(pr->pr_type, data + o, + pr->pr_datasz, ELF_COMPAT, arch); + if (ret) + return ret; + + *off = o + step; + return 0; +} + +#define NOTE_DATA_SZ SZ_1K +#define GNU_PROPERTY_TYPE_0_NAME "GNU" +#define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME)) + +static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr, + struct arch_elf_state *arch) +{ + union { + struct elf_note nhdr; + char data[NOTE_DATA_SZ]; + } note; + loff_t pos; + ssize_t n; + size_t off, datasz; + int ret; + bool have_prev_type; + u32 prev_type; + + if (!IS_ENABLED(CONFIG_ARCH_USE_GNU_PROPERTY) || !phdr) + return 0; + + /* load_elf_binary() shouldn't call us unless this is true... */ + if (WARN_ON_ONCE(phdr->p_type != PT_GNU_PROPERTY)) + return -ENOEXEC; + + /* If the properties are crazy large, that's too bad (for now): */ + if (phdr->p_filesz > sizeof(note)) + return -ENOEXEC; + + pos = phdr->p_offset; + n = kernel_read(f, ¬e, phdr->p_filesz, &pos); + + BUILD_BUG_ON(sizeof(note) < sizeof(note.nhdr) + NOTE_NAME_SZ); + if (n < 0 || n < sizeof(note.nhdr) + NOTE_NAME_SZ) + return -EIO; + + if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 || + note.nhdr.n_namesz != NOTE_NAME_SZ || + strncmp(note.data + sizeof(note.nhdr), + GNU_PROPERTY_TYPE_0_NAME, n - sizeof(note.nhdr))) + return -ENOEXEC; + + off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ, + ELF_GNU_PROPERTY_ALIGN); + if (off > n) + return -ENOEXEC; + + if (note.nhdr.n_descsz > n - off) + return -ENOEXEC; + datasz = off + note.nhdr.n_descsz; + + have_prev_type = false; + do { + ret = parse_elf_property(note.data, &off, datasz, arch, + have_prev_type, &prev_type); + have_prev_type = true; + } while (!ret); + + return ret == -ENOENT ? 0 : ret; +} + static int load_elf_binary(struct linux_binprm *bprm) { struct file *interpreter = NULL; /* to shut gcc up */ @@ -689,6 +804,7 @@ static int load_elf_binary(struct linux_binprm *bprm) int load_addr_set = 0; unsigned long error; struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL; + struct elf_phdr *elf_property_phdata = NULL; unsigned long elf_bss, elf_brk; int bss_prot = 0; int retval, i; @@ -726,6 +842,11 @@ static int load_elf_binary(struct linux_binprm *bprm) for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++) { char *elf_interpreter; + if (elf_ppnt->p_type == PT_GNU_PROPERTY) { + elf_property_phdata = elf_ppnt; + continue; + } + if (elf_ppnt->p_type != PT_INTERP) continue; @@ -819,9 +940,14 @@ out_free_interp: goto out_free_dentry; /* Pass PT_LOPROC..PT_HIPROC headers to arch code */ + elf_property_phdata = NULL; elf_ppnt = interp_elf_phdata; for (i = 0; i < interp_elf_ex->e_phnum; i++, elf_ppnt++) switch (elf_ppnt->p_type) { + case PT_GNU_PROPERTY: + elf_property_phdata = elf_ppnt; + break; + case PT_LOPROC ... PT_HIPROC: retval = arch_elf_pt_proc(interp_elf_ex, elf_ppnt, interpreter, @@ -832,6 +958,11 @@ out_free_interp: } } + retval = parse_elf_properties(interpreter ?: bprm->file, + elf_property_phdata, &arch_state); + if (retval) + goto out_free_dentry; + /* * Allow arch code to reject the ELF at this point, whilst it's * still possible to return an error to the code that invoked @@ -913,7 +1044,8 @@ out_free_interp: } } - elf_prot = make_prot(elf_ppnt->p_flags); + elf_prot = make_prot(elf_ppnt->p_flags, &arch_state, + !!interpreter, false); elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE; @@ -1056,7 +1188,8 @@ out_free_interp: if (interpreter) { elf_entry = load_elf_interp(interp_elf_ex, interpreter, - load_bias, interp_elf_phdata); + load_bias, interp_elf_phdata, + &arch_state); if (!IS_ERR((void *)elf_entry)) { /* * load_elf_interp() returns relocation diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index aaad4ca1217e..13a087bc816b 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -17,6 +17,8 @@ #include <linux/elfcore-compat.h> #include <linux/time.h> +#define ELF_COMPAT 1 + /* * Rename the basic ELF layout types to refer to the 32-bit class of files. */ @@ -28,11 +30,13 @@ #undef elf_shdr #undef elf_note #undef elf_addr_t +#undef ELF_GNU_PROPERTY_ALIGN #define elfhdr elf32_hdr #define elf_phdr elf32_phdr #define elf_shdr elf32_shdr #define elf_note elf32_note #define elf_addr_t Elf32_Addr +#define ELF_GNU_PROPERTY_ALIGN ELF32_GNU_PROPERTY_ALIGN /* * Some data types as stored in coredump. diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8d382d4ec067..b73cdbb221e8 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -638,6 +638,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_ARCH_1)] = "ar", [ilog2(VM_WIPEONFORK)] = "wf", [ilog2(VM_DONTDUMP)] = "dd", +#ifdef CONFIG_ARM64_BTI + [ilog2(VM_ARM64_BTI)] = "bt", +#endif #ifdef CONFIG_MEM_SOFT_DIRTY [ilog2(VM_SOFTDIRTY)] = "sd", #endif diff --git a/include/linux/elf.h b/include/linux/elf.h index e3649b3e970e..5d5b0321da0b 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -2,6 +2,7 @@ #ifndef _LINUX_ELF_H #define _LINUX_ELF_H +#include <linux/types.h> #include <asm/elf.h> #include <uapi/linux/elf.h> @@ -21,6 +22,9 @@ SET_PERSONALITY(ex) #endif +#define ELF32_GNU_PROPERTY_ALIGN 4 +#define ELF64_GNU_PROPERTY_ALIGN 8 + #if ELF_CLASS == ELFCLASS32 extern Elf32_Dyn _DYNAMIC []; @@ -31,6 +35,7 @@ extern Elf32_Dyn _DYNAMIC []; #define elf_addr_t Elf32_Off #define Elf_Half Elf32_Half #define Elf_Word Elf32_Word +#define ELF_GNU_PROPERTY_ALIGN ELF32_GNU_PROPERTY_ALIGN #else @@ -42,6 +47,7 @@ extern Elf64_Dyn _DYNAMIC []; #define elf_addr_t Elf64_Off #define Elf_Half Elf64_Half #define Elf_Word Elf64_Word +#define ELF_GNU_PROPERTY_ALIGN ELF64_GNU_PROPERTY_ALIGN #endif @@ -56,4 +62,41 @@ static inline int elf_coredump_extra_notes_write(struct coredump_params *cprm) { extern int elf_coredump_extra_notes_size(void); extern int elf_coredump_extra_notes_write(struct coredump_params *cprm); #endif + +/* + * NT_GNU_PROPERTY_TYPE_0 header: + * Keep this internal until/unless there is an agreed UAPI definition. + * pr_type values (GNU_PROPERTY_*) are public and defined in the UAPI header. + */ +struct gnu_property { + u32 pr_type; + u32 pr_datasz; +}; + +struct arch_elf_state; + +#ifndef CONFIG_ARCH_USE_GNU_PROPERTY +static inline int arch_parse_elf_property(u32 type, const void *data, + size_t datasz, bool compat, + struct arch_elf_state *arch) +{ + return 0; +} +#else +extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz, + bool compat, struct arch_elf_state *arch); +#endif + +#ifdef CONFIG_ARCH_HAVE_ELF_PROT +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, + bool has_interp, bool is_interp); +#else +static inline int arch_elf_adjust_prot(int prot, + const struct arch_elf_state *state, + bool has_interp, bool is_interp) +{ + return prot; +} +#endif + #endif /* _LINUX_ELF_H */ diff --git a/include/linux/linkage.h b/include/linux/linkage.h index 9280209d1f62..d796ec20d114 100644 --- a/include/linux/linkage.h +++ b/include/linux/linkage.h @@ -105,7 +105,7 @@ /* === DEPRECATED annotations === */ -#ifndef CONFIG_X86 +#ifndef CONFIG_ARCH_USE_SYM_ANNOTATIONS #ifndef GLOBAL /* deprecated, use SYM_DATA*, SYM_ENTRY, or similar */ #define GLOBAL(name) \ @@ -118,10 +118,10 @@ #define ENTRY(name) \ SYM_FUNC_START(name) #endif -#endif /* CONFIG_X86 */ +#endif /* CONFIG_ARCH_USE_SYM_ANNOTATIONS */ #endif /* LINKER_SCRIPT */ -#ifndef CONFIG_X86 +#ifndef CONFIG_ARCH_USE_SYM_ANNOTATIONS #ifndef WEAK /* deprecated, use SYM_FUNC_START_WEAK* */ #define WEAK(name) \ @@ -143,7 +143,7 @@ #define ENDPROC(name) \ SYM_FUNC_END(name) #endif -#endif /* CONFIG_X86 */ +#endif /* CONFIG_ARCH_USE_SYM_ANNOTATIONS */ /* === generic annotations === */ diff --git a/include/linux/mm.h b/include/linux/mm.h index 5a323422d783..b61ca546eea4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -325,6 +325,9 @@ extern unsigned int kobjsize(const void *objp); #elif defined(CONFIG_SPARC64) # define VM_SPARC_ADI VM_ARCH_1 /* Uses ADI tag for access control */ # define VM_ARCH_CLEAR VM_SPARC_ADI +#elif defined(CONFIG_ARM64) +# define VM_ARM64_BTI VM_ARCH_1 /* BTI guarded page, a.k.a. GP bit */ +# define VM_ARCH_CLEAR VM_ARM64_BTI #elif !defined(CONFIG_MMU) # define VM_MAPPED_COPY VM_ARCH_1 /* T if mapped copy of data (nommu mmap) */ #endif diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index 34c02e4290fe..c6dd0215482e 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -36,6 +36,7 @@ typedef __s64 Elf64_Sxword; #define PT_LOPROC 0x70000000 #define PT_HIPROC 0x7fffffff #define PT_GNU_EH_FRAME 0x6474e550 +#define PT_GNU_PROPERTY 0x6474e553 #define PT_GNU_STACK (PT_LOOS + 0x474e551) @@ -367,6 +368,7 @@ typedef struct elf64_shdr { * Notes used in ET_CORE. Architectures export some of the arch register sets * using the corresponding note types via the PTRACE_GETREGSET and * PTRACE_SETREGSET requests. + * The note name for all these is "LINUX". */ #define NT_PRSTATUS 1 #define NT_PRFPREG 2 @@ -429,6 +431,9 @@ typedef struct elf64_shdr { #define NT_MIPS_FP_MODE 0x801 /* MIPS floating-point mode */ #define NT_MIPS_MSA 0x802 /* MIPS SIMD registers */ +/* Note types with note name "GNU" */ +#define NT_GNU_PROPERTY_TYPE_0 5 + /* Note header in a PT_NOTE section */ typedef struct elf32_note { Elf32_Word n_namesz; /* Name size */ @@ -443,4 +448,10 @@ typedef struct elf64_note { Elf64_Word n_type; /* Content type */ } Elf64_Nhdr; +/* .note.gnu.property types for EM_AARCH64: */ +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 + +/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */ +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) + #endif /* _UAPI_LINUX_ELF_H */ diff --git a/lib/Kconfig b/lib/Kconfig index 5d53f9609c25..e831e1f01767 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -80,6 +80,9 @@ config ARCH_USE_CMPXCHG_LOCKREF config ARCH_HAS_FAST_MULTIPLIER bool +config ARCH_USE_SYM_ANNOTATIONS + bool + config INDIRECT_PIO bool "Access I/O in non-MMIO mode" depends on ARM64 diff --git a/tools/testing/selftests/wireguard/qemu/debug.config b/tools/testing/selftests/wireguard/qemu/debug.config index 5909e7ef2a5c..807fa7dc60b8 100644 --- a/tools/testing/selftests/wireguard/qemu/debug.config +++ b/tools/testing/selftests/wireguard/qemu/debug.config @@ -58,7 +58,6 @@ CONFIG_RCU_EQS_DEBUG=y CONFIG_USER_STACKTRACE_SUPPORT=y CONFIG_DEBUG_SG=y CONFIG_DEBUG_NOTIFIERS=y -CONFIG_DOUBLEFAULT=y CONFIG_X86_DEBUG_FPU=y CONFIG_DEBUG_SECTION_MISMATCH=y CONFIG_DEBUG_PAGEALLOC=y |